Four renal "oncocytomas" were observed between July 1974 and January 1975 at University Hospital. A review of all renal cell neoplasms previously classified as carcinomas since 1952 was conducted to determine whether this cluster of tumors represented a recent increase in incidence or whether other renal "oncocytomas" had gone unrecognized in the past. The 23-year review of 194 carcinomas yielded an additional nine "oncocytomas." None had appeared prior to 1964, whereas almost half were found… CONTINUE READING